To enable coaxial relative rotation of a pair of elements it is established practice to provide a race body on one element and a bearing body on the other element. The two bodies provide a bearing structure that enables relative rotation to occur between the two elements. The bearing bodies may have matching continuous ring-shaped surfaces to make a friction bearing, or rollers or balls to make for roller or ball bearings, for example. In any event, damage to the race destroys its bearing function, and the system must be repaired, usually by replacing the damaged race.
This may not be much of a problem in conventional machinery in convenient locations. In a factory, a large bearing can be dismantled, the damaged parts removed and replaced, and the bearing reassembled. There is no particular difficulty in what is basically a time-consuming inconvenience. However, there are installations wherein such a solution is not acceptable. One example is found in relatively large space-based installations. In such locations the physical effort required to repair a structure in this way is often simply not available, and storage of spare parts is not practicable. The need to wait for replacement parts to be sent aloft, or the need for an astronaut to make substantial exertions to repair the structure can cripple a project.
It is necessary to anticipate that serious damage may be done to bearing systems, for example as the consequence of collision with space junk. Unless the system is inherently provided with means to restore the bearing function without requiring the use of spare or replacement parts, and unless it can be repaired with only minimal physical effort, that system is seriously flawed for such applications.
It is an object of this invention to provide redundancy in a bearing system which enables the ready restoration of function after damage to a race without requiring the use of replacement parts, or of requiring more effort than the loosening, reversal, and retightening of the blocks, or even in some cases more simply, the disablement of a selected part or parts. Replacement parts and their attendant delays and expenses, and repair techniques which require substantial exertion, are thereby eliminated.